Self-heating systems and methods for rapidly heating a comestible substance

ABSTRACT

Self-heating systems for rapidly and effectively heating a comestible substance are disclosed. Self-heating systems generally include a reaction chamber and a heating chamber. The heating chamber contains a substance to be heated. The reaction chamber contains reactants that, when contacted, exothermically react. The containers and reactants can be configured to heat at least six fluid ounces of comestible substance in less than one minute. The solid chemical reactant mixture can comprise magnesium chloride, calcium chloride, and/or calcium oxide. Methods for heating at least six fluid ounces of comestible substance in less than one minute are also provided.

REFERENCE TO ANY PRIORITY APPLICATIONS

Any and all applications for which a foreign or domestic priority claimis identified in the Application Data Sheet as filed with the presentapplication are hereby incorporated by reference under 37 CFR 1.57.

BACKGROUND OF THE INVENTIONS

1. Field of the Inventions

The present inventions generally relate to self-heating systems andmethods, and more particularly to self-heating systems and methods forrapidly heating a comestible substance.

2. Description of the Related Art

In today's on-the-go consumer society, there is increasing demand for aconvenient and effective container which may be used by consumers toheat consumable products, such as coffee, tea, milk, soup, and manyother types of beverage or food products, at any time and any location,without having access to any conventional heating means, such as acoffee maker, microwave, cook top, etc. Self-heating technology based onan exothermic reaction between different reagents is often used in suchcontainers. Typically, two or more reagents are initially separated by abreakable partition in the container, and when heat needs to begenerated, the partition is broken to allow the mixing of the reagents,thereby creating an exothermic reaction for heat generation. Typically,the reagents employed for generating the heat include at least a solidmaterial, such as calcium oxide, and a liquid material, such as water.

The prior art self-heating systems, however, have many shortcomings. Forexample, the speed for heating larger volumes of beverage or food totemperature is generally slower than desired, especially in today'son-the-go consumer society. Moreover, the temperature of the beverage orfood typically cannot be maintained for an extended period of time afterthe exothermic reaction. Further, the self-heating containers are oftennot designed for effective separation, deployment, and mixing of thechemical reactants therein. Thus, there is a need for an improved oralternative self-heating system and method for heating beverage andfood.

SUMMARY OF THE INVENTIONS

The preferred embodiments of the present invention provide an improvedself-heating system that is engineered to control and optimize theperformance of the system and ameliorate at least some of theshortcomings of prior art systems. Implementations of the variouscombinations of pre-selected product and process parameters and featuresdisclosed herein result in certain improved self-heating systems havingperformance characteristics which the inventors believe have not beenachieved by prior art self-heating systems. However, no single one ofthe disclosed parameters and features is solely responsible for theirdesirable attributes and not all of the parameters and features arenecessary to achieve the advantages of the systems. After consideringthis discussion, and particularly after reading the section entitled“Detailed Description of the Preferred Embodiments,” one will understandhow the features of the preferred embodiments provide advantages overprior art.

Certain embodiments of self-heating systems and methods disclosed hereinare compact and disposable self-heating containers capable of heating atleast 6 fluid ounces of a comestible substance, such as coffee or tea,from room temperature to at least 145° F. in less than one minute. Somesuch embodiments require agitation of reactants during an exothermicreaction while others require little, if any, agitation of the reactantsduring the exothermic reaction. Some embodiments also have compactconfigurations that allow the self-heating containers to be easilycarried and used.

Certain embodiments of self-heating containers disclosed herein provideimproved apparatuses for maintaining reactants, which are intended forexothermic reaction, separated until initiation of the exothermicreaction is desired. At that time, such embodiments predictably andreliably release at least one reactant from a first compartment into asecond compartment to initiate the exothermic reaction. Some embodimentsare configured to facilitate rapid mixture of the reactants. Someembodiments additionally or alternatively promote uniform mixing of thereactants. Various embodiments resist environmental effects therebyproviding long shelf-lives.

In accordance with at least one of the embodiments disclosed herein, aself heating system for heating a comestible substance comprises acontainer body defining a volume for holding about 6-12 fluid ounces ofa comestible substance and a reaction chamber adjacent the containerbody adapted to house a plurality of reactants. At least two of thereactants are separated by a rupturable barrier. Rupture of the barrierallows contact between the reactants to form a reaction mixture andinitiate a multi-stage exothermic reaction. The exothermic reactiongenerates sufficient heat during a first stage of the reaction to cause,for an initial duration, at least a portion of the contents of thereaction chamber to have a temperature of at least 212° F. A portion ofthe heat from the exothermic reaction is rapidly transferred to thecomestible substance in the container body. The amount and rate of heattransferred are at least sufficient to heat the comestible substancefrom a temperature of about 80° F. to a temperature of about 145° F.within one minute of the initiation of the exothermic reaction. Incertain embodiments, the heat is sufficient to heat the comestiblesubstance from about 75° F. to about 145° F. within one minute of theinitiation of the exothermic reaction. In certain other embodiments, theheat is sufficient to heat the comestible substance from about 70° F. toabout 145° F. Preferably, the heat transferred is controlled in a mannersuch that the comestible substance does not reach a temperature greaterthan about 212° F., preferably not greater than 185° F. In certainimplementations, the heat transferred is controlled in a manner suchthat the comestible substance does not exceed a target temperature ofabout 145° F. After rapidly raising the initial temperature of thecomestible substance, the exothermic reaction is configured to generatea lesser amount of heat during a second stage of the exothermic reactionthan during the first stage of the exothermic reaction. A portion of theheat generated during the second stage of the reaction is alsotransferred to the comestible substance at a rate that is capable ofmaintaining the temperature of the comestible substance preferably at orabove 145° F. for at least 2 minutes. The self-heating system isconfigured such that about 60%-90% of the heat generated from theexothermic reaction is transferred to the comestible substance when thecoefficient of heat transfer from the reaction mixture to the comestiblesubstance is about 0.0167 to about 0.0833 BTU/(ft²·sec.·° F.). Incertain embodiments, the self-heating system is configured to direct apreferred amount of heat to the comestible substance by controlling theheat transfer coefficient of the reaction mixture to comestiblesubstance and the heat transfer coefficient of the reaction mixture tothe cup exterior so that significantly more heat is being driven to thecomestible substance than through the cup walls. In one embodiment, thecoefficients of heat transfer are selected such that about 60%-90% ofthe heat generated is directed to the comestible substance and about10%-40% of the heat generated is dissipated through the cup walls. Inother embodiments, the cup walls comprise an insulating materialselected to result in a lower heat transfer coefficient from thereaction mixture to the cup exterior than that from the reaction mixtureto the comestible substance.

In accordance with at least one of the embodiments disclosed herein, aself-heating container for heating a comestible substance of a certainvolume, preferably between about 6-12 fluid ounces, comprises a firstchamber for accommodating the comestible substance, a second chamber foraccommodating chemical reactants, and a rupturable barrier adapted toseparate the chemical reactants, preferably separating an aqueoussolution from a solid chemical reactant mixture. The second chamber isin thermal communication with the first chamber. The rupturable barrieris disposed within the second chamber in a manner so as to divide thesecond chamber into a first compartment and a second compartment. Thefirst compartment is adapted to receive the aqueous solution and thesecond compartment is adapted to receive the solid chemical reactantmixture. Rupture of the barrier allows mixing between the aqueoussolution and the solid chemical reactant mixture to form an exothermicreaction mixture. A surface between the first chamber and the secondchamber is contacted by the exothermic reaction mixture to facilitateheat transfer from the first chamber to the second chamber. In oneembodiment, the surface comprises at least a portion of the exteriorwall of the first chamber. In a preferred implementation, the containeris configured so that the ratio of the surface area contacted by theexothermic reaction mixture to the volume of the comestible substance tobe heated is at least 2.5 square inches per 1 cubic inch. Reaction ofthe aqueous solution and the solid chemical reactant mixture results ina temperature above 212° F. within the second chamber soon after thereaction begins and maintains a temperature of at least 170° F. withinthe second chamber for at least one minute. At least 60% of the heatgenerated by reaction of the aqueous solution and the solid chemicalreactant mixture is transferred to the comestible substance. Thecoefficient of heat transfer from the reaction of the aqueous solutionand the solid chemical reactant mixture to the comestible substance ispreferably at least 0.0167 BTU/(ft²·sec.·° F.).

In accordance with at least one of the embodiments disclosed herein, acontainer for a comestible substance is provided. The containergenerally comprises an outer body having a height of between about 5 to8 inches and an average cross-sectional area of between about 3 to 4square inches. The container further comprises a heating chamberdisposed within the outer body and has a volume adapted to receivebetween about 10 to 18 fluid ounces of a comestible substance, areaction chamber disposed within the outer body and adapted to house apredetermined amount of reactants and allow the reactants to undergo anexothermic chemical reaction and generate heat. Preferably, thecoefficient of heat transfer from the reaction chamber to the comestiblesubstance is at least between about 0.0167 BTU/(ft²·sec.·° F.) to 0.0833BTU/(ft²·sec.·° F.) such that the temperature of the comestiblesubstance can be raised from room temperature to about 145° F. withinone minute of the initiation of the exothermic chemical reaction andwherein the temperature of the comestible substance does not exceedabout 212° F.

In accordance with at least one of the embodiments disclosed herein, acontainer for a comestible substance comprises a first chamber, a secondchamber, and a breakable barrier. The first chamber receives thecomestible substance, which has a volume. The second chamber is inthermal communication with the first chamber. The breakable barrier isdisposed within the second chamber between a first compartment and asecond compartment. A first reactant is located within the firstcompartment and a second reactant is located within the secondcompartment. In some embodiments, a third reactant is also locatedwithin the second compartment. When the barrier is broken, a reaction ofthe first reactant with the second reactant and/or the third reactantgenerates steam within the second chamber and thereafter maintains anaverage temperature of about 170° F. for at least one minute, preferablybetween about 1 to 2 minutes. In a preferred implementation, theconfiguration of the container in combination with predetermined amountsof each reactant result in the combined volumes of the reactants beingsufficient to cover a surface separating the first and second chamberssuch that the ratio of the surface area covered by the reactants to thevolume of the comestible substance to be heated is at least 2.5 squareinches per cubic inch. In another preferred implementation, theconfiguration of the container and heat transfer properties of thematerial are preferably selected to result in at least 60% of the heatgenerated by the chemical reaction in the second chamber to betransferred to the comestible substance in the first chamber. Thecoefficient of heat transfer from the reaction of the aqueous solutionand the solid chemical reactant mixture to the comestible substance isat least 0.0167 BTU/(ft²·sec.·° F.).

In accordance with at least one of the embodiments disclosed herein, acontainer for changing the temperature of a comestible substancecomprises an outer container body, an inner container body, and abarrier. The outer container body defines a recess and comprises amovable portion. The inner container body defines a recess toaccommodate the comestible substance. The inner container body isconnected to the outer container body to form a chamber. The barrier ispositioned within the chamber to divide the chamber into a firstcompartment and a second compartment. At least a first reactant ispositioned within the first compartment. At least a second reactant ispositioned within the second compartment. The barrier comprises a firstbarrier member and a second barrier member. The first harrier member hasan opening and is substantially fixed relative to the outer containerbody. The second barrier member is removably attached to the firstbarrier member to seal the opening. Movement of the movable portion ofthe outer container body separates the second barrier member from thefirst barrier member to allow contact between the first reactant and thesecond reactant. A reaction involving at least the first reactant and atleast the second reactant causes the temperature of the comestiblesubstance to change.

In accordance with at least one of the embodiments disclosed herein, acontainer for a comestible substance comprises an inner container body,an outer container body, a barrier, and an actuator. The inner containerbody forms a receptacle to receive the comestible substance. The outercontainer body is attached to the inner container body forming a chamberbetween the outer container body and the inner container body. Thebarrier is disposed within the chamber and at least partially separatesa first compartment of the chamber from a second compartment of thechamber. The barrier comprises a first barrier member and a secondbarrier member. The first barrier member is removably mechanicallycoupled to the second barrier member. The actuator is configured toengage the second barrier member to decouple the second barrier memberfrom the first barrier member and permit one of the first reactant andthe second reactant to move between the first compartment and the secondcompartment. Preferably, the second barrier member will not decouplefrom the first barrier member unless a predetermined amount of force isapplied to the actuator. The predetermined amount of force is preferablyselected to inhibit accidental removal of the barrier member.

In accordance with at least one of the embodiments disclosed herein, amethod for preparing a self-heating container comprises placing a firstreactant in a first compartment of the container and placing a secondreactant in a second compartment of the container. The method furthercomprises positioning at least a first barrier member between the firstcompartment and the second compartment. The method further comprisesmechanically engaging a second barrier member with the first barriermember to separate the first compartment from the second compartmentsuch that contact between the first reactant and the second reactant isinhibited and such that movement of the actuator rapidly disengages thesecond barrier member from the first barrier member to allow at leastone of the first reactant and the second reactant to move between thefirst compartment and the second compartment to contact the other of thefirst reactant and the second reactant.

In accordance with at least one of the embodiments disclosed herein, aself-heating container designed to withstand pressure of the steamgenerated from the exothermic reaction therein is provided. Thecontainer generally comprises an outer shell defining a space, an innercontainer disposed within the space wherein the outer shell and theinner container are coupled together by a double seam. The containerfurther comprises a seal plate disposed inside the shell and extendsannularly along the interior wall of the outer shell so as to providestructural reinforcement. The seal plate serves multiple functions byproviding a barrier between the reactants and also providing structuralreinforcement. In one embodiment, the container incorporating thestructural reinforcements is capable of withstanding at least 17 psig ofinternal pressure without rupturing. In another embodiment, thecontainer incorporating the structural reinforcements is capable ofwithstanding an internal pressure of between about 40-45 psig withoutrupturing.

All of these embodiments are intended to be within the scope of thepresent inventions herein disclosed. These and other embodiments of thepresent inventions will become readily apparent to those skilled in theart from the following detailed description of the preferred embodimentshaving reference to the attached figures, the inventions not beinglimited to any particular preferred embodiment(s) disclosed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a self-heating system according to oneembodiment, shown in the form of a container.

FIG. 2 is a cross-sectional view of the container of FIG. 1.

FIG. 3 is a top perspective view of a pull tab lid of the container ofFIG. 1 according to one embodiment.

FIG. 4 is a bottom perspective view of a drinking lid of the containerof FIG. 1 according to one embodiment.

FIG. 5 is a top perspective view of the drinking lid of FIG. 4.

FIG. 6 is an enlarged view of section 6 of the container shown in FIG.2.

FIG. 7 is a bottom view of a barrier portion of the container of FIG. 1according to one embodiment.

FIG. 8 is a top view of the barrier portion of FIG. 7.

FIG. 9 is a bottom view of a removable barrier portion incorporated aspart of a container according to one embodiment.

FIG. 10 is an enlarged view of section 10 of the container shown in FIG.2.

FIG. 11 is a top view of an outer container body of the container ofFIG. 1 according to one embodiment.

FIG. 12 is a side view of a barrier portion according to one embodiment.

FIG. 13 is a top view of the barrier portion of FIG. 12.

FIG. 14 is a cross-sectional view of a container comprising the barrierportion of FIGS. 12 and 13 according to one embodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In various embodiments, the self-heating system disclosed herein ispreferably a compact self-heating container configured to hold acomestible substance, such as about 6-12 fluid ounces of a beverage, andrapidly heat the substance by reaction of chemicals that are held withinthe container and separated from the substances to be heated. Inpreferred implementations, the self-heating system is configured so thatthe amount and rate of heat transferred to the comestible substance arecontrolled in accordance with the volume of substance to be heated toensure rapid heating of the substance without overheating. The preferredembodiments of the self-heating system incorporate engineeredimprovements in various aspects of the system, including improvedcontainer construction and design, optimized heat transfer properties,and controlled heat generation systems. Each of these attributes willnow be discussed in turn.

I. CONTAINER CONSTRUCTION, AND DESIGN

Certain embodiments of self-heating containers will now be describedmore fully hereinafter with reference to the accompanying drawings. Thecontainers may, however, be embodied in many different forms and shouldnot be construed as limited to the embodiments set forth herein.

FIG. 1 illustrates a perspective view of a container 10, according toone embodiment. As shown in FIG. 1, the container 10 has an elongated,canister-shaped body configured to be held by a person's hand like mostindividual beverage containers. Referring to the cross-sectionalillustration of FIG. 2, the container 10 includes an outer containerbody 12, an inner container body 14 disposed within the outer containerbody 12, a reaction chamber 13 for generating heat from exothermicreactions, and a heating chamber 15 for receiving beverage, food item,or any other consumable products or substances to be heated. Thereaction chamber 13 is disposed in a space between the outer and innercontainer bodies 12, 14 and the heating chamber 15 is located inside theinner container body 14. The reaction chamber 13 is preferably arrangedto substantially surround the heating chamber 15 to facilitate heattransfer thereto in a manner to be described in greater detail below. Inpreferred implementations, the container further includes a firstcompartment 16 and a second compartment 22, which are disposed withinthe reaction chamber 13 and separated by a breakable partition orbarrier 28.

In the embodiment shown in FIGS. 1 and 2, the heating chamber 15 islocated inside the inner container body 14 while the reaction chamber 13is positioned between the inner and outer container bodies andsubstantially surrounds the heating chamber 15. However, theconfiguration and relative positioning of the heating chamber andreaction chamber can vary in other embodiments of the invention. In someembodiments, the reaction chamber 13 is disposed inside the innercontainer body, preferably as part of an insertable module, while theheating chamber containing the beverage or food items is positioned inthe space between the inner and outer container bodies surrounding thereaction chamber. Further details regarding some of the alternativeconfigurations are found in U.S. Patent Application Publication Number2003/0205224, published Nov. 6, 2003, which is hereby incorporated byreference in its entirety.

As in the embodiment illustrated in FIG. 2, the inner container body 14can be generally cylindrical. In such embodiments, the inner containerbody 14 can have a cross-section which is generally circular, square,triangular or other shape. In some embodiments, the inner container body14 can have other shapes such as generally conical, generallyfrustoconical, generally hemi-spherical, or other shapes, alone or incombination.

In a preferred embodiment, the inner container body 14 is constructedwith a material having high thermal conductivity. For example, the innercontainer body 14 can be constructed of a metallic material such asaluminum or a polymeric material, such as polyolefin. In someembodiments, the outer container body 12 can be generally cylindrical.In such embodiments, the outer container body 12 can have across-section which is generally circular, square, triangular or othershape. In some embodiments, the outer container body 12 can have othershapes such as generally conical, generally frustoconical, generallysemi-spherical, or other shapes.

The container 10 can include a lid 2, such as is illustrated in FIGS. 2and 3, covering the inner container body 14 to enclose the substanceinside the heating chamber 15. The inner container body 14 can include arim 36 to provide a region for attachment with the lid 2. The lid 2preferably obstructs an opening of the inner container body 14 to keepinside the substance to be heated, as shown in FIG. 2. In someembodiments, the lid 2 is sealed to the rim 36 of the inner containerbody 14. Referring to FIG. 3, in some embodiments, the container 10 caninclude a lid 2 with a pull tab 38. The lid 2 can be made of anysuitable material such as aluminum, alone or in combination with othermaterials.

In some embodiments, the heating chamber 15 can be large enough toaccommodate about 6 fluid ounces, 8 fluid ounces, 10 fluid ounces, 12fluid ounces or more of comestible substance. In one embodiment, theheating chamber 15 has a total volume of about 9.8 fluid ounces. Thevolume of the heating chamber 15 in preferably greater than the volumeof the comestible substance to be heated. For example, the enclosedheating chamber volume can be about 10%, 20%, 30% or more than thevolume of the comestible substance. In one embodiment, the heatingchamber 15 in the inner container body 14 is sufficiently large to holda liquid capacity of greater than or equal to about 100 mL (3.38 fluidounces), preferably between about 100 mL to 200 mL (3.38 to 6.76 fluidounces). In another embodiment, the heating chamber 15 is sufficientlylarge to hold a liquid capacity of greater than or equal to about 200 mL(6.76 fluid ounces), preferably between about 200 mL to 300 mL (6.76 to10.14 fluid ounces). In various embodiments, the heating chamber 15 maybe sufficiently large to hold a comestible substance with a volume of atleast six fluid ounces (177 mL), preferably between about 6 to 12 fluidounces (177 mL to 355 mL), preferably about 10 fluid ounces (296 mL),preferably about 12 fluid ounces (355 mL), preferably between about 12to 18 fluid ounces (355 mL to 532 mL), or more. While the heatingchamber is adapted to receive a large volume of a comestible substance,the container preferably has a compact configuration that can be easilycarried by a person. In one implementation, the container has a heightof between about 5 and 8 inches, more preferably about 5.7 inches, ormore preferably about 7.2 inches, and an average cross-sectional area ofabout 7 to 12 square inches, more preferably about 7.25 square inches,or more preferably about 11.5 square inches. In another implementation,the container has an average diameter of between about 7 and 12 inches.

In addition to or in alternative to the lid 2, the container 10 caninclude a lid 4 to facilitate consumption of the comestible substance.Such lids can have various configurations. For example, the drinking lid4, illustrated in FIGS. 4 and 5, is configured to snap onto thecontainer 10 and includes an orifice 5 to enable the consumer to consumethe substance inside the container 10.

Referring again to FIG. 2, the inner container body 14 can be connectedto the outer container body 12. The illustrated outer container body 12is larger than the inner container body 14 and is shaped to receive theinner container body 14 with the reaction chamber 13 between the outercontainer by 12 and the inner container body 14. For example, the outercontainer body 12 can comprise a recess. In some embodiments, the outercontainer body 12 is sufficiently large to accommodate the innercontainer body 14 and the reactants.

The reaction chamber 13 is preferably sized to accommodate thereactants. In some embodiments, the volume of the reaction chamber 13exceeds the volume of the reactants by an amount sufficient to allowunrestrained reaction of the reactants. In some embodiments, the volumeof the reaction chamber 13 is larger than the volume of the reactants bya sufficient amount to permit free movement of the reactants during aperiod of agitation of the reactants, such by shaking, for example,after the barrier 28 has been opened. In one embodiment, the volume ofthe reaction chamber is approximately 10%-25% greater than the volume ofthe reactants.

Referring to FIG. 6, in some embodiments, the inner and outer containerbodies 14, 16 are secured using a double seam 171 at the lip 17 of theinner container body 14 and the lip 19 of the outer container body 12.The double seam construction provides structural reinforcement to thecontainer so that the container can better withstand pressure from thesteam generated from the exothermic reactions. In some embodiments, theinner container body 14 and the outer container body 12 may be formed asa single integrated structure in which the lip 17 of the inner containerbody 14 and the lip 19 of the outer container body 12 are continuous.Alternatively, the lip 17 of the inner container body 14 may be sealedwith the lip 19 of the outer container body 12, using, for example,conventional sealing technologies such as thermal welding, crimping, orseaming.

With continued reference to FIG. 2, in one embodiment, the outercontainer body 12 is constructed with an insulating material to directthe heat toward the inner container body 14 and to keep the outsidesurface of the outer container body 12 from getting too hot for the userto hold. For example, the outer container body 12 can be made of anappropriate polyolefin. In some embodiments, the outer container body 12can be made of polypropylene, polyethylene or other suitable plasticmaterial.

In one embodiment, the outer container body 12 can include a protruding,flexible bottom 26, which, in a relaxed state, protrudes downward.Referring to FIG. 2, when force is exerted on the bottom 26, it can bepushed inward and directed to the inner container body 14. In someembodiments, the bottom 26 can be integrally formed with the outercontainer body 12, as illustrated in FIG. 2, such as by injectionmolding or extrusion molding. Alternately, the bottom 26 can be sealedto a surface of the outer container body 12, such as the inside surface,using any welding process.

As shown in FIG. 2, the first compartment 16 is preferably disposedinside the outer container body 12, underneath the inner container body14 in a spaced relationship. The second compartment 22 is preferablybetween the inner container body 14 and the first compartment 16. Insome embodiments, the second compartment 22 is adjacent to the innercontainer body 14, as shown in FIG. 2, for example. In some embodimentsthe first compartment 16 is adjacent to the inner container body 14,while the second compartment 22 is spaced from the inner container body14. In some embodiments, the first compartment 16 and/or the secondcompartment 22 is adjacent to the heating chamber 15, such that at leastone of the compartments is in thermal communication with the heatingchamber 15.

The first compartment 16 is configured to hold at least one reactant,such as a solid chemical reactant mixture or an aqueous solution. Thesecond compartment 22 is configured to hold at least another reactant.Either or both of the compartments 16, 22 can hold 2, 3, 4, or morereactants. In some embodiments, one of the compartments contains anaqueous reactant or solution, while the other compartment contains oneor more solid reactants before the barrier 28 is opened.

The first compartment 16 can be made of any suitable material able towithstand heat such as polypropylene, polyethylene, or aluminum. Thefirst compartment 16 can be integrally formed with the outer containerbody 12, as illustrated in FIG. 2. Alternatively, the first compartment16 can be formed separately from the outer container body 12. Furtherdetails regarding such constructions are provided in U.S. patentapplication Ser. No. 11/559,873, entitled “SELF-HEATING CONTAINER” andfiled on Nov. 14, 2006; U.S. patent application Ser. No. 11/559,878,entitled “SELF-HEATING CONTAINER” and filed on Nov. 14, 2006; and U.S.patent application Ser. No. 11/862,120, entitled “SELF-HEATINGAPPARATUSES USING SOLID CHEMICAL REACTANTS” and filed on Sep. 26, 2007;the entireties of all of which are hereby incorporated by referenceherein.

In some embodiments, the second compartment 22 contains a sufficientamount of a first reactant that when the container is inverted to beupside down, as compared to the orientation illustrated in FIG. 1, thefirst reactant covers annularly the outer surface of the inner containerbody 14. In some embodiments, the reactants together generally orsubstantially cover the entire exterior surface of the inner containerbody 14, which contains the reaction chamber during at least a portionof the duration of the reaction between the reactants. In at least oneembodiment, the container is configured so that the reactants togethercontact about 54 cubic inches of the inner container body 14 whichcontains a heating chamber that holds about 6 fluid ounces of comestiblesubstance and has a total capacity of about 9.8 fluid ounces. In someembodiments, during at least a portion of the duration of the reaction,the reactants together generally or substantially cover at least about2.5 square inches of the exterior surface of the inner container body 14per cubic inch of the comestible substance to be heated, which may beall of or less than the entire surface area of the inner container body14. In some embodiments, the reactants together generally orsubstantially cover at least about 3.0 square inches, or at least about5.2 square inches, or at least about 4.3 square inches of the exteriorsurface of the inner container body 14 per cubic inch of comestiblesubstance to be heated. Such configurations, which may use the innercontainer body 14 to hold the substance to be heated, improve theefficiency of heat transfer between the reactants and the substance tobe heated. The surface area of the inner container body 14 can beincreased, for example, by providing fins that extend from the innercontainer body 14 into the reaction chamber 13, by corrugating thesurface of the inner container body 14, or both.

As shown in FIG. 2, the partition or barrier 28 can be positioned withinthe reaction chamber 13 between the first compartment 16 and the secondcompartment 22. The barrier 28 can at least partially separates thefirst compartment 16 from the second compartment 22. In someembodiments, the barrier 28 divides the reaction chamber 13 into thefirst compartment 16 and the second compartment 22. The partition orbarrier 28 can be ruptured, broken, or otherwise opened to permitcontact between the reactants.

In some embodiments, the barrier 28 comprises a first barrier member 42and a second barrier member 44. The first barrier member 42 has anopening 46 and the second barrier member 44 is removably attach to thefirst barrier member 42 such that the second barrier member 44 obstructsthe opening 46. In some embodiments, the first barrier member 42 and thesecond barrier member 44 can be made of polyolefin, while in otherembodiments one or both of the barrier members 42, 44 can be made ofother materials.

In some embodiments, the opening 46 is located in a central region ofthe first barrier member 42. In some embodiments, the opening 46 issufficiently large to allow the contents of the first compartment 16 tosubstantially evacuate into the second compartment 22 in one second orless. In some embodiments the opening 46 can be sufficiently large toallow the contents of the first compartment 16 to substantially evacuateinto the second compartment in 0.75 second or less, 0.5 second or less,or 0.25 second or less. Rapid evacuation of the contents of onecompartment into the other compartment can expedite reaction of thereactants held in the first compartment 16 and the second compartment 22prior to opening the barrier 28.

The first barrier member 42 can extend from the opening 46 to an outerperiphery 48, as illustrated in FIGS. 7 and 8. The outer periphery 48 ofthe first barrier member 42 can be shaped to engage another portion ofthe container 10. For example, the outer periphery 48 of the firstbarrier member 42 can be shaped to conform to an inner surface of theouter container body 12. Thus, in the embodiment illustrated in FIGS. 2and 10, the periphery 48 of the first barrier member 42 is generallycircular, as illustrated in FIGS. 7 and 8. However, the periphery 48 thefirst barrier member 42 can have other shapes.

The first barrier member 42 can be fixed to a portion of the container10 to maintain the position of the first barrier member 42 between firstcompartment 16 and the second compartment 22. In the embodimentillustrated in FIGS. 2 and 10, the first barrier member 42 is fixed to aportion of the outer container body 12. In some embodiments, the firstbarrier member 42 can be fixed to a vessel configured to hold one ormore of reactants and that is formed separately from the outer containerbody 12.

The first barrier member 42 can be fixed to the portion of the container12 by friction, mechanical interference, adhesives, welding, or by othersuitable fixation means or a combination thereof. In the embodimentillustrated in FIGS. 2 and 10, the first barrier member 42 comprises afirst ring 50 extending downwardly from a lower side of the firstbarrier member 42 that engages a correspondingly sized and shapedportion 52 of the outer container body 12.

The first ring 50 and the portion 52 of the outer container body 12 canmechanically interfere with each other to inhibit disengagement of thefirst barrier member 42 from the outer container body 12. For example,in the embodiment illustrated in FIGS. 2 and 10, the first ring 50 cancomprise a first bead 54 and the portion 52 of the outer container body12 can comprise a second bead 56. The first bead 54 and the second bead56 are sized, shaped, and positioned such that one or both of the firstbead 54 and the second bead 56 are deflected from their coupledpositions as the second barrier member 44 is detached from the innercontainer body 12. The first ring 50 can sealingly engage the portion 52of the outer container body 12 to inhibit, or preferably prevent, fluidcommunication between the first barrier member 42 and the outercontainer body 12.

In some embodiments, the first barrier member 42 can further comprise awall 58 extending downwardly from the lower side of the first barriermember 42. The wall 58 can be sized, shaped, and positioned to engagethe portion 52 of the outer container body 12. The wall 58 can inhibitdisengagement of the first barrier member 42 from the outer containerbody 12 by frictional engagement and/or mechanical interference with theouter container body 12, such as, the portion 52 for example. The wall58 can comprise texturing or other features on a surface that engagesthe outer container body 12. For example, the wall 58 can comprise oneor more protrusions (not shown) that extend from the wall 58 forengagement with the outer container body 12. Such protrusions cancomprise rings, bumps, or features having other shapes. In addition toor in alternative to sealing engagement between the first ring 50 andthe portion 52 of the outer container body 12, the wall 58 can sealinglyengage the outer container body 12 to inhibit, or preferably prevent,fluid communication between the first barrier member 42 and the outercontainer body 12.

Any or all of the first ring 50 of the first barrier member 42, thefirst bead 54 of the first barrier member 42, the wall 58 of the firstbarrier member 42, the portion 52 of the outer container body 12, andthe second bead 56 of the outer container body 12 can be formed as asingle continuous loop, which can be circular. In some embodiments, oneor more of the first ring 50 of the first barrier member 42, the firstbead 54 of the first barrier member 42, the wall 58 of the first barriermember 42, the portion 52 of the outer container body 12, and the secondbead 56 of the outer container body 12 can be formed as a discontinuousseries of constituent members.

The first barrier member 42 can be generally configured as a plate. Incertain embodiments, the first barrier member 42 is configured as a sealplate and coupled to the inner sidewalls of the container in a manner soas to also provide additional structural reinforcement for the containerso that the container can withstand higher pressure from steam generatedby the exothermic reaction In some embodiments, the first barrier member42 can be frustoconical, as illustrated in FIGS. 2 and 10. However, thefirst barrier member 42 can have other configurations such as generallyor substantially flat.

The embodiment of the first barrier member 42 that is illustrated inFIG. 2 comprises at least one frustoconical surface 60. Thefrustoconical surface 60 can direct the contents of the firstcompartment 16 through the opening 46 into the second compartment 22 toexpedite contact between the contents of the first compartment 16 andthe contents of the second compartment 22.

Referring to FIG. 7, the first barrier member 42 can comprise aplurality of ribs 62. The ribs 62 can extend between the opening 46 inthe periphery 48 of the first barrier member 42. The ribs 62 canincrease the rigidity of the first barrier member 42. Additionally oralternatively, the ribs 62 can direct the contents of the firstcompartment 16 toward the opening 46. While the first barrier member 42illustrated in FIG. 7 comprises eight ribs 62, the first barrier member42 can comprise more or less than eight ribs 62 in other embodiments.For example, the first barrier member 42 can comprise 2, 3, 4, 5, 6, 7,8, 9, 10, 11, or 12 ribs or more.

The second barrier member 44 can be removably attached to the firstbarrier member 42 to obstruct the opening 46, as illustrated in FIG. 2,for example. The second barrier member 44 can be removably attached tobe first barrier member 42 by friction, mechanical interference,adhesives, welding them or by other suitable attachment means or acombination thereof. In some embodiments, the second barrier member 44can be configured as a cap.

In the embodiment illustrated in FIGS. 2 and 10, the second barriermember 44 is removably mechanically coupled to the first barrier member42. The second barrier member 44 can be removably mechanically attachedto the first barrier member 42 by moving a least portion of one of thefirst barrier member 42 and the second barrier member 44 over a least aportion of the other of the first barrier member 42 and the secondbarrier member 44. The first barrier member 42 and the second barriermember 44 can be configured such that movement of the first barriermember 42 away from the second barrier member 44 is inhibited bymechanical interference between at least a portion of the first barriermember 42 and at least a portion of the second barrier member 44.

The second barrier member 44 can comprise one or more engagement members64, as shown in FIGS. 9 and 10, configured to engage a portion 66 of thefirst barrier member 42. The second barrier member 44 can comprise fourengagement members 64, as illustrated in FIG. 9, or more than or fewerthan four engagement members. In some embodiments, the engagementmembers 64 are evenly spaced, as illustrated in FIG. 9, while in otherembodiments the engagement members 64 may not be evenly spaced.

The engagement members 64 of the second barrier member 44 can beconnected to a first ring 68 of the second barrier member 44, as shownin FIGS. 9 and 10. The engagement members 64 can form a ring thatprotrudes radially from the first ring 68 of the second barrier member44.

The portion 66 of the first barrier member 42 can be formed as a ringthat extends upwardly from an upper side of the first barrier member 42,as illustrated in FIGS. 2 and 8. The engagement members 64 and theportion 66 can be configured such that the first barrier member 42 andthe second barrier member 44 are removably mechanically coupled bymoving the engagement members 64 over the portion 66. The engagementmembers 64 and the portion 66 are sized, shaped, and positioned suchthat engagement members 64, the portion 66 or both are deflected fromtheir coupled positions as the second barrier member 44 is detached fromthe first barrier member 42. In some embodiments, the portion 66 cancomprise a ring that radially protrudes from the portion 66.

In some embodiments, the second barrier member 44 can comprise a wall70. The wall 70 can extend downwardly from the lower side of the secondbarrier member 44. The wall 70 can be sized shaped and positioned toengage the portion 66 of the first barrier member 42. The wall 70 caninhibit disengagement of the first barrier member 42 from the secondbarrier member 44 by frictional engagement and/or mechanicalinterference with the portion 66 of the first barrier member 42. Forexample, a frictional force between the wall 70 and the portion 66 caninhibit disengagement of the first barrier member 42 from the secondbarrier member 44. Additionally or alternatively, the wall 70 caninhibit deflection of the portion 66 away from the engagement members64.

In addition to or in alternative to inhibiting the disengagement of thefirst barrier member 42 from the second barrier member 44, the wall 70can facilitate rapid disengagement of the first barrier member 42 fromthe second barrier member 44. For example, as illustrated in theembodiment of FIG. 10, the wall 70 can comprise an inclined face 72 thatfaces the portion 66. Once the forces inhibiting disengagement of thefirst barrier member 42 from the second barrier member 44 are overcome,inclined face 72 tends to push the second barrier member 44 away fromthe first barrier member 42.

The second barrier member 44 sealingly engages the first barrier member42. For example, in some embodiments, the wall 70 of the second barriermember 44 sealingly engages the portion 66 of the first barrier member42. In some embodiments, the first ring 68 of the second barrier member44 sealingly engages the first barrier member 42.

In some embodiments, the first barrier member 42 and the second barriermember 44 form a snap cap assembly, in which the second barrier member44 comprises a cap that snaps onto the first barrier member 42.

As discussed above, the size of the opening 46 can be sufficiently largeto rapidly evacuate the contents of one compartment into the other.However, as the size of the opening 46 increases, the likelihood ofleakage between first barrier member 42 and the second barrier member 44may also increase. In one embodiment, the cross-sectional area of theopening is preferably about 10% to 35% of the cross-sectional area ofthe container centered at the centerline of the container. In oneimplementation, the opening has a diameter of about 1 inch (about 24 mm)and the diameter of the cross-sectional area at the centerline of thecontainer is about 2⅜″ (about 62 mm). In another implementation, thearea of the opening is about 452.4 mm² and the total cross-sectionalarea at the centerline of the container is about 3,019 mm². In anotherimplementation, the cross-sectional area of the opening 46 is about20%-80%, more preferably 30%-50%, more preferably about 40% of thecross-sectional area of the seal plate.

The second barrier member 44 can comprise an extension 74, as shown inFIGS. 2 and 9, for example. When the second barrier member 44 isassembled with the first barrier member 42 and the outer container body12, the extension 74 can extend toward the bottom 26 of the outercontainer body 12. When the first barrier member 42, the second barriermember 44, and the outer container body 12 are assembled, the lowerextent of the extension 74 can be within the range of movement of theflexible bottom 26 of the outer container body 12 such that movement ofthe bottom 26 toward barrier 28 can separate the second barrier member44 from the first barrier member 42.

The extension 74 of the second barrier member 44 can comprise aplurality of fins 78, as shown in FIG. 9. Although the extension 74 thatis illustrated in FIG. 9 comprises six fins 78, the extension 74 cancomprise other numbers of fins in other embodiments. The fins 78 can beinterconnected, as illustrated in FIG. 9.

Configurations of the extension 74 that comprise fins 78 can provide oneor more advantages. In some embodiments, such configurations canfacilitate molding. In some embodiments, the cross-sectional area ofsuch configurations can be significantly smaller than thecross-sectional area of the opening 46 to allow flow of material throughthe opening 46, while maintaining sufficient rigidity to transmitsufficient force to disengage the second barrier member 44 from thefirst barrier member 42. In some embodiments, the fins 78 can direct thecontents of the first compartment 16 into the second compartment 22.

The bottom 26 can be a movable portion of the outer container body 12and can protrude away from the barrier 28 in a relaxed state. The bottom26 can move between a relaxed position and a fully-deflected position.In some embodiments, when the first barrier member 42, the secondbarrier member 44, and the outer container body 12 are assembled and thebottom 26 is in the relaxed position, the bottom 26 at its nearest pointto the second barrier member 44 is spaced from the second barrier member44 by a distance of approximately 0.1 inch or approximately 0.126 inchin some embodiments. In some embodiments, when the bottom 26 is in thefully-deflected position, the second barrier member 44 must becompletely detached from the first barrier member 42. In someembodiments, the bottom 26 causes the second barrier member 44 toseparate from the first barrier member 42 when the bottom 26 is in aposition between the relaxed position and the fully-deflected position.In some embodiments, displacement of the second barrier member 44 by thebottom 26 over a distance of about 0.1 inch is sufficient to decouplethe first barrier member 42 from the second barrier member 44. In someenvironments, application of a force of at least 2 pounds to the bottom26 in a direction toward the barrier 28 is sufficient to move the bottom26 a sufficient distance to separate the first to remember 42 and thesecond remember 44.

In some embodiments, separation of the second barrier member 44 from thefirst barrier member 42 such that the second barrier member 44 no longerobstructs the opening 46 allows contact between the contents of thefirst compartment 16 and the contents of the second compartment 22. Forexample, in some embodiments, rupture of the barrier 28 allows contactbetween the aqueous solution and the solid chemical reactant mixture.

In some embodiments, when a user desires to heat the substance in thecontainer 10, the user can invert the container 10 such that thecontainer 10 is upside down, as compared to the orientation of thecontainer 10 that is shown in FIG. 1, and then exert pressure on thebottom 26 to push the bottom towards the inner container body 14. Theexerted pressure will push the bottom 26 towards the barrier 28 toengage and move the second barrier member 44 sufficiently to dislodgethe secondary member 44 from the first barrier member 42, therebyopening the barrier 28. Upon opening of the barrier 28, at least a firstreactant will be released into the second compartment 22 to mix with atleast a second reactant. The user may shake the container 10 tofacilitate mixture of the reactants, which creates an exothermicreaction to generate heat. Heat from the exothermic reaction istransferred to the beverage or food substance provided inside theheating chamber 15. After the substance is heated, the user may removethe pull tab lid 2, and as an option, attach the drinking lid 4 to thecontainer 10, for consuming the heated substance.

In some embodiments, the flexible bottom 26 can comprise an extension inaddition to or in alternative to the extension 74 of the second barriermember 44. In such embodiments, the extension that extends from theflexible bottom 26 and the second barrier member 44 can be in a spacedrelationship when a container 10 is assembled such that movement of thebottom 26 can disengage the second barrier member 44 from the firstbarrier member 42.

In some embodiments, the flexible bottom 26 can comprise a wall 76(FIGS. 2 and 11) extending into the first compartment 16 toward thesecond barrier member 44, as shown in FIG. 2. The wall 76 is positionedin proximity to the extension 74 of the second barrier member 44 andextends sufficiently far into the first compartment 16 to at leastpartially surround the extension 74 at some point in the range ofmovement of the bottom 26. As the flexible bottom 26 is moved toward thesecond barrier member 44 to disengage the second barrier member 44 fromthe first barrier member 42, the wall 76 inhibits tilting of thesecondary member 44 relative to the first barrier member 42 tofacilitate complete disengagement of the second barrier member 44 fromthe first barrier member 42. The wall 76 can comprise a single member,or a plurality of members as shown in FIG. 11. Segmented configurationsof the wall 76, such as the illustrated in FIG. 11, can advantageouslyimprove the flexibility of the bottom 26 as compared to a singlecontinuous wall 76.

In some embodiments, the first barrier member 42 can comprise acentering feature 80 to generally maintain alignment between the firstbarrier member 42 and the second barrier member 44. For example, thecentering feature 80 that is illustrated in FIGS. 12-14 comprises aplurality of members 82 extending upwardly from an upper side of thefirst barrier member 42. In the illustrated embodiment, the centeringfeature 80 comprises eight upstanding members 80. In some embodiments,the centering feature 80 can comprise more or fewer than eightupstanding members 80. For example, in some embodiments, the centeringfeature 80 can comprise 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, or moreupstanding members 80. The upstanding members 80 can be positionedgenerally in proximity to the opening 46 such that surfaces 84 of theupstanding members 80 that face the opening 46 facilitate alignment ofthe second barrier member 44 with the first remember 42. In someembodiments, the surfaces 84 of the upstanding members 80 can direct thesecond barrier member 44 toward engagement with the first barrier member42 during assembly to obstruct the opening 46. Additionally oralternatively, in some embodiments, the surfaces 84 of the upstandingmembers 80 can facilitate alignment of the secondary barrier member 44and the first barrier member 42 after the second barrier member 44 hasbeen disengaged from the first barrier member 42. Such alignment afterdisengagement can advantageously inhibit the second barrier member 44from obstructing movement of the contents of the first compartment 16into the second compartment 22. The upstanding members 80 can be spacedfrom one another, as illustrated in FIGS. 12-14, or may beinterconnected to form, for example, a single structure extending fromthe first barrier member 42. The upstanding members 80 can be evenlyspaced around the opening 46, as shown in FIG. 13, or maybe irregularlyspaced.

In some embodiments, an open, upper end of the first compartment 16 canbe covered with a breakable material which acts as a barrier to keep thereactants in the first compartment 16 and the second compartment 22 frommixing until the partition is broken. For example, the breakablepartition can be made of a foil, such as an aluminum foil, that can bepierced and/or cut by a breaking device. Further details regardingbreakable partitions and breaking devices are provided in U.S. patentapplication Ser. No. 11/862,120, filed Sep. 26, 2007, which is herebyincorporated by reference herein in its entirety.

In some embodiments, the parts of the above-described container 10 aremade of materials that can withstand at least the maximum temperaturethat would be reached from the exothermic reaction, which can be atleast two hundred and fifty degrees Fahrenheit (250° F.) in someembodiments. In some embodiments, parts of the container 10 are made ofmaterials having a high-class transition temperature, a low heatcapacity, or both. Parts of the above-described container 10 that formportions of the reaction chamber 13 are made of materials that sealwell. Parts of the container 10 that conduct heat between the reactionchamber 13 and the heating chamber 15 are made of materials that conductheat well. Other parts of the container 10 are preferably made ofmaterials that insulate well.

In some embodiments, the container 10 includes an insulating layer 40disposed within the chamber 13 between the outer container body 12 andthe inner container body 14. The insulating layer 40 can be positionedalong the inner surface of the outer container body within the reactionchamber to inhibit heat loss from the container. Positioning theinsulating layer 40 within the reaction chamber 13 between the outercontainer body 12 and the reactants inhibits absorption by the outercontainer body 12 of heat created within the reaction chamber 13,thereby directing a greater proportion of the heat generated to thesubstance to be heated and reducing heating times as compared toconfigurations that omit the insulating layer 40.

The insulating layer 40 can be made of any suitable insulating materialsuch as Styrofoam, expandable polystyrene, urethane, fiberglass,sprayable foam. In some embodiments, in which the insulating layer 40 ismade of expandable polystyrene, the insulating layer 40 can have athickness of a least 0.070 inch or greater, 0.085 inch or greater, 0.100inch or greater. The density of such expandable polystyrene can be atleast 1.75 pounds per cubic foot, 2.85 pounds per cubic foot or 3.5pounds per cubic foot.

The insulating layer 40 can be in the form of a sleeve. The insulatinglayer 40 can form one or more walls of the second enclosed chamber,which can form at least a part of the reaction chamber, to inhibit lossof the heat generated from an exothermic reaction and direct such heatto the inner container body. The insulating layer 40 can reduce thelikelihood that the outer surface of the container will become too hotfor a consumer to hold. The insulating layer 40 can be used with any ofthe containers described in this application.

In one embodiment, the insulating layer is structurally molded resultingin a rigid foam, such as an expanded polystyrene foam, which iscontoured to the inner shape of the outer container body. The insulatingsleeve may be designed to drop into place within the outer containerbody and be secured by friction. In one embodiment, the insulatingsleeve insulates the entire inner surface of the outer container body.In one embodiment, the inner surface of the insulating sleeve maybetextured to assist agitation and reaction of the first and secondreactants. For example, the insulating sleeve may have a surfaceroughness of no less than 0.001 inches. In one embodiment, theinsulating sleeve is resistant to high heat and compatible with theheating slurry formed by the mixture of the first and second reactants.In one embodiment, the insulating sleeve density can be adjusted toresult in the highest insulating values required by the design andspecification of the container.

The following table provides measured values for insulating polystyrenefoam used for certain preferred embodiment of the present invention. Asshown below, the insulating foam preferably has a thermal conductivityvalue of between 0.012 to 0.086 BTU/(ft²·sec.·° F.), which in turncauses a temperature differential of between 36° F. to about 45.4° F.

A B C D E F G Thickness as 0.133 0.102 0.125 0.143 0.122 0.155 0.097measured (in.) Density (g/cc) 0.049 0.043 0.041 0.045 0.056 0.037 0.012Surface Temperature 170.3 168.6 168 170.7 167.8 168.2 163.7 (F.)Temperature Drop 36.5 36 42.1 45.4 41.4 43.5 36.5 (F.) Thermalconductivity 0.0245 0.072 0.071 0.075 0.073 0.086 0.012 BTU/(ft² · sec.· ° F.) R factor 0.452 0.118 0.146 0.158 0.140 0.150 0.667 (ft² · hr · °F./BTU)

In one embodiment, the insulating sleeve can be manufactured using aprocess called “Dry Heat Expansion”. In this process, multiple sphericalbeads, each of which is of an approximate size of granular salt, arepositioned in a mold to form the insulating sleeve. After heat isintroduced to the mold, the granular beads expand to fill the moldcavity, with their density decreasing from 39 lb/cubic ft. to 3lbs/cubic ft. or below, depending on the specific thickness limits setfor the insulating sleeve. The expanded beads may form a smoothinsulating surface, or be further adjusted using any one of theconventional processes to generate certain roughness in the surface,such as an “orange peel” condition.

In one embodiment, the reaction chamber has a plurality of walls made ofa material with a thermal conductivity selected to substantially inhibitheat generated from the exothermic reaction from transferring from thereaction chamber through the walls to the exterior of the chamber.Preferably, the material comprising the reaction chamber wall is indirect contact with the exothermic reaction product, and may have anon-smooth surface texture adapted to assist the release of molecules orbubbles when water vapor or steam is generated due to the exothermicreaction in the reaction chamber. In one embodiment, the material has asurface roughness of at least 0.001 inch.

In some embodiments, the container 10 has a thermal efficiency of atleast 60% during the period between initiation of the reaction and thetime when the comestible substance has reached the desired temperature,thermal efficiency being the amount of heat transferred to thecomestible substance within the heating chamber 15 divided by the totalamount of heat produced by the exothermic reaction. In some suchembodiments, the container 10 has a thermal efficiency of at least 70%,at least 80%, or at least 90%.

In some embodiments, that portion of the heat generated by theexothermic reaction which is not transferred to the comestible substanceis not more than 40% of the total heat generated by the exothermicreaction. In some such embodiments, that portion of the heat generatedby the exothermic reaction which is not transferred to the comestiblesubstance is not more than 30%, 20%, or 10% of the total heat generatedby the exothermic reaction. Such heat that is generated by theexothermic reaction and not transferred to the comestible substance maybe retained in the reactants, retained in the container 10, transferredto the environment surrounding the container 10, or some combinationthereof.

In some embodiments, the container 10 can have a coefficient of heattransfer between the exothermic reaction and the comestible substance ofat least 0.0167 BTU/(ft²·sec.·° F.) during the reaction. In some suchembodiments, the container 10 can have a coefficient of heat transferbetween the exothermic reaction comestibles substance of at least 0.0278BTU/(ft²·sec.·° F.), at least 0.0556 BTU/(ft²·sec.·° F.), or at least0.0833 BTU/(ft²·sec.·° F.) during the reaction.

In one embodiment, containers 10 described above with reference to FIG.2 can be manufactured and assembled in the following process. The outercontainer body 12 and the inner container body 14 can be separatelymanufactured using conventional manufacturing methods such as injectionmolding. If the inside of the inner container body 14 is made ofaluminum, it can be coated with any FDA approved coating to protect thebeverage or food products from contacting raw aluminum. The first andsecond barrier members 42 and 44 can be separately made using injectionmolding or other methods. After each individual piece is manufactured,they can be assembled following the steps below. First, the outercontainer body is placed into a holder in a filling line. The firstbarrier member 42 can be sealing secured to the outer container body 12.At least one reactant is then placed in the first compartment 16 throughthe opening 46 in the first barrier member 42. Thereafter, the secondbarrier member 42 is sealing engaged with the first barrier member 42 toenclose the first compartment 16. At least one additional reactant isplaced in the outer container body 12 in the second compartment 22. Theinner container body 14 is placed into the outer container body 12. Thereactant in the second compartment 22 may surround the inner containerbody 14, and the bottom of the inner container body 14 can be proximateto but spaced from the first enclosed compartment 16. The outercontainer body 12 and the inner container body 14 can be sealedtogether, such as, for example, by forming a double seam at adjoininglips 17 and 19. Beverage, food or other consumable products can beplaced inside the inner container body 14. The consumable product can besealed in the inner container body 14 using a pull tab lid 2 placed onthe inner container body 14. The inner container body 14 and the pulltab lid 2 sealed using a conventional method. The underside of the pulltab lid 2 can be coated with any FDA approved coating to protect thebeverage or food products from contacting raw aluminum. A snap-ondrinking lid is attached to the top of the container. Other appropriatemanufacturing and assembling methods well known to those skilled in theart may also be employed to manufacture and assemble the containers.

In operation, a user may press the bottom 26 of the outer container body12 toward the inner container body 14, and as a result of the forceexerted upon the bottom 26, the second barrier member 44 will be pushedtoward the inner container body 14 so that the second barrier member 44at least partially disengages from the first barrier member 42 to openthe barrier 28. Subsequently, the reactant within the first enclosedcompartment 16 will be released and mix with the other second reactantprovided within the second compartment 22. The heat generated from theexothermic reaction between the two reactants will be transferred andexchanged to heat the substance in the heating chamber 15. When thesubstance is heated and ready to be consumed, the user can remove thepull tab lid 2 and put the snap-on drinking lid 4 on the container 10.To maximize and facilitate the mixture of two reactants, the user caninvert the container 10 such that the container 10 is upside down,compared to the orientation illustrated in FIG. 1, before pressing thebottom 26 of the outer container body 12, and optionally, shake thecontainer after the barrier is opened to cause the mixture.

II. HEAT GENERATION

Heat generation for the self-heating container disclosed herein can beachieved by one or more exothermic reactions involving two or morereactants. For example, the self-heating container can comprise anaqueous solution and a solid chemical reactant mixture. In someembodiments, the solid chemical reactant mixture can include magnesiumchloride, calcium chloride, and/or calcium oxide. In such embodiments,the proportions of magnesium chloride, calcium chloride, and/or calciumoxide may be from 10 to 55 parts, from 10 to 35 parts, and from 10 to 20parts, respectively.

In some embodiments, the total combined mass of magnesium chloride,calcium chloride, and calcium oxide is less than about 100 g. In someembodiments, the solid chemical reactant mixture consists essentially ofmagnesium chloride, calcium chloride, calcium oxide, and an organicacid. In other embodiments, the solid chemical reactant mixture consistsessentially of magnesium chloride, calcium chloride, and calcium oxidesuch as anhydrous calcium oxide. The magnesium chloride may be selectedfrom the group consisting of anhydrous magnesium chloride, dihydratemagnesium chloride, or a mixture thereof. The calcium chloride may beselected from the group consisting of anhydrous calcium chloride,monohydrate calcium chloride, dihydrate calcium chloride, or a mixturethereof. In some embodiments, the calcium chloride is dihydrate calciumchloride and the magnesium chloride is anhydrous magnesium chloride.Where the calcium oxide, magnesium chloride or calcium chloride isspecified as a particular hydration state (e.g. anhydrous, monohydrate,or dihydrate), one of skill will understand that trace amounts of otherhydration states may be present as impurities. Similarly, the calciumoxide may contain trace amounts of calcium hydroxide as an impurity.

Upon contacting the aqueous solution with the solid chemical reactantmixture, the aqueous solution reacts with, for example dissolves, thesolid chemical reactant mixture thereby producing heat. Where theaqueous solution dissolves the solid chemical reactant mixture, the heatproduced is derived at least in part from the heat of solution of thesolid chemical reactant mixture. The heat of solution occurs when anamount of chemical is dissolved in an aqueous solution, such as water ora solution containing water as the solvent and diluted. The heat ofsolution is specific to the exact form of the chemical species.

In certain embodiments, upon contacting the aqueous solution with thesolid chemical reactant mixture, the aqueous solution reacts with thesolid chemical reactant mixture thereby producing, within five minutes,a heating mixture, having a temperature of at least 200° F. Morepreferably, a heating mixture having a temperature of at least 200° F.is produced within four minutes, three minutes, two minutes, or oneminute. In some embodiments, the heating mixture can have a temperatureof at least 200° F. within less than one minute, for example, between15-30 seconds, between 10-30 seconds, between 10-40 seconds, or between30-50 seconds. In other embodiments, the heating mixture can have atemperature of at least 200° F. in 30 seconds or less, 15 seconds orless, 10 seconds or less, five seconds or less, two seconds or less, orone second or less. The temperature may be at least 225° F. orapproximately 250° F. The temperature may also be from 200° F. to 250°F. In some embodiments, a heating mixture having a temperature of atleast 212° F., preferably between 212° F. to 220° F., is produced in twominutes or less, one minute more or less, thirty seconds or less, 15seconds or less, 5 seconds or less, two seconds or less, or one secondor less. In some embodiments, sufficient heat is generated by reactionof the aqueous solution and the solid chemical reactant mixture toproduce steam from the aqueous solution.

The temperature of the heating mixture described in the precedingparagraph can be maintained for at least one minute such as between oneto two minutes, or more preferably at least two minutes, such as betweentwo to three minutes, three minutes such as between three to fourminutes, four minutes such as between four to five minutes, five minutessuch as between five to six minutes, or ten minutes. In someembodiments, the heating solution can have an average temperature of atleast 170° F. over at least one minute, preferably between one to twominutes. The heating mixture is preferably the mixture formed from thereaction of the solid chemical reactant mixture (or portions thereof)with the aqueous solution.

In some embodiments, the self-heating container comprises a heatingchamber for containing a substance to be heated. The container includesa reaction chamber adjacent to the heating chamber. The reaction chambercomprises a first compartment and a second compartment. The firstcompartment comprises at least a first reactant and the secondcompartment includes at least a second reactant. The first reactant andthe second reactant can be solid chemical reactant mixtures or aqueoussolutions. In certain implementations, where the first reactant is thesolid chemical reactant mixture, the second reactant is the aqueoussolution. And where the first reactant is the aqueous solution, thesecond reactant is the solid chemical reactant mixture. In certain otherimplementations, both the first and second reactants are aqueoussolutions. The container further comprises a breakable partition orbarrier between the first compartment and the second compartment. Uponbreaking the barrier, the first and second reactants contact each otherand form an exothermic reaction. The barrier or partition can be brokenby rupturing or otherwise opening the barrier or partition to allow atleast one reactant to pass there through.

The substance to be heated may be any appropriate substance, but aretypically liquids, solids, or mixtures thereof. In a preferredembodiment, the substance is a comestible substance (e.g., liquid and/orsolid), such as a beverage (e.g., coffee, tea, water, or hot chocolate),a soup, or a solid food within a fluid to be cooked (e.g., noodleswithin water), etc.

The self-heating container may include an insulating layer on the innersurface of the reaction chamber. In some embodiments, the insulatinglayer includes a textured surface.

In some embodiments, the self-heating container is used for heating aliquid. The container includes an aqueous solution and a solid chemicalreactant mixture having a mass of less than 100 g. Upon contacting theaqueous solution with the solid chemical reactant mixture, the aqueoussolution dissolves the solid chemical reactant mixture thereby producinga heating solution capable of heating at least six ounces of the liquidto at least 120° F. More preferably, the liquid is heated to at least130° F., 140° F., or 150° F. In some embodiments, the liquid is heatedto at least 120° F. within two minutes, preferably within one minute, ofcontacting the aqueous solution with the solid chemical reactantmixture. In some embodiments, upon breaking the breakable partition, theaqueous solution reacts with the solid chemical reactant mixture therebyproducing a heating mixture capable of heating at least six ounces ofthe liquid to a temperature from 130° F. to 150° F.

In some embodiments, the solid chemical reactant mixture can have a massof less than 75 g. In other embodiments, the solid chemical reactantmixture can have a mass of 75 g or more. The aqueous solution can have avolume of less than 100 mL. The aqueous solution can have a volume of100 mL or more.

In certain embodiments, the solid chemical reactant mixture used cancomprise an anhydrous magnesium chloride and/or dihydrate magnesiumchloride, a calcium chloride, and a calcium oxide (e.g., anhydrouscalcium chloride such as quicklime). The calcium chloride may beanhydrous calcium chloride, monohydrate calcium chloride, dihydratecalcium chloride, or a mixture thereof. In some embodiments, the calciumchloride is monohydrate calcium chloride, dihydrate calcium chloride, ora mixture thereof. In other embodiments, the calcium chloride isdihydrate calcium chloride.

As the term suggests, solid chemical reactant mixtures are in solidform, meaning that the chemical reactants within the mixture do notinclude liquid reactants. In some embodiments, the anhydrous magnesiumchloride and/or dihydrate magnesium chloride, calcium chloride, andcalcium oxide are thoroughly mixed together when added to theself-heating container. In other embodiments, the anhydrous magnesiumchloride and/or dihydrate magnesium chloride, calcium chloride, andcalcium oxide are present as layers in the self-heating apparatus. Thus,in some embodiments, the anhydrous magnesium chloride and/or dihydratemagnesium chloride, calcium chloride, and calcium oxide are not actuallymixed together when forming the solid chemical reactant mixture. Theterm “mixture,” when used in the context of a solid chemical reactantmixture herein, means a substance composed of two or more components,each of which retains its own properties.

The solid chemical reactant mixtures described herein providessurprising and advantageous properties for use within the self-heatingcontainers, such as those described herein. It is typically desirable toachieve a high instantaneous temperature in the heating apparatus and ahigh heat transfer rate through the container into the substance to beheated. Thus, upon introducing such mixtures in an aqueous solution,significant heat is produced quickly and is maintained effectively overthe desired period. For example, where the heating apparatus is a selfheating container comprising a heating chamber for containing asubstance to be heated, the mixture produces, upon reaction with anaqueous solution, sufficient heat energy to heat a desired amount of thesubstance and maintain the heat for a desired amount of time.

In some embodiments, the solid chemical reactant mixture consistsessentially of an anhydrous magnesium chloride and/or dihydratemagnesium chloride, a calcium chloride, and a calcium oxide. In otherembodiments, the solid chemical reactant mixture consists essentially ofan anhydrous magnesium chloride and/or dihydrate magnesium chloride, acalcium chloride, a calcium oxide, and an organic acid. In someembodiments, the solid chemical reactant mixture consists of ananhydrous magnesium chloride and/or dihydrate magnesium chloride, acalcium chloride, and a calcium oxide. In other embodiments, the solidchemical reactant mixture consists of an anhydrous magnesium chlorideand/or dihydrate magnesium chloride, a calcium chloride, a calciumoxide, and an organic acid. In other embodiments, the solid chemicalreactant mixture consists of an anhydrous magnesium chloride, a calciumchloride, a calcium oxide, and an organic acid.

In some embodiments, the mixture employs anhydrous magnesium chlorideand not dihydrate magnesium chloride. As described above, the calciumchloride may be anhydrous calcium chloride, monohydrate calciumchloride, dihydrate calcium chloride, or a mixture thereof. In someembodiments, the calcium chloride is a mixture of monohydrate calciumchloride, and dihydrate calcium chloride. The calcium oxide (also knownas quicklime) may be present in the mixture in any appropriate solidform.

The organic acid is an acid containing carbon atoms. The organic acid istypically a weak acid containing a carboxyl (—COOH) group, such ascitric acid, acetic acid, or lactic acid.

The proportions of anhydrous magnesium chloride and/or dihydratemagnesium chloride, calcium chloride, and/or calcium oxide are from 10to 55 parts, from 10 to 35 parts, and from 10 to 20 parts, respectively.In some embodiments, the total combined mass of magnesium chlorideand/or dihydrate magnesium chloride, calcium chloride, and calcium oxideis less than 100 g. In some embodiments, the total combined mass ofmagnesium chloride and/or dihydrate magnesium chloride, calciumchloride, and calcium oxide is greater than about 100 g. In oneembodiment, the solid reactant mixture comprises about 16 g of magnesiumchloride, about 30 g of calcium chloride, and about 20 g of calciumoxide. In some embodiments, the mixture forms part of an aqueoussolution. The proportions of anhydrous magnesium chloride and/ordihydrate magnesium chloride, calcium chloride, and/or calcium oxide maybe adjusted according to the teachings herein to heat the aqueoussolution sufficiently to produce steam.

III. METHODS OF HEATING A SUBSTANCE IN A CHAMBER

A method of heating a substance in a chamber (e.g., the heating chamber)can include contacting an aqueous solution with a solid chemicalreactant mixture to form a heating mixture, which may be a solution(e.g., solubilizing the solid chemical reactant mixture with the aqueoussolution). As described above, the heating mixture makes contact withthe walls of the heating chamber. The solid chemical reactant mixturecan include a first chemical reactant, a second chemical reactant, and athird chemical reactant. The first chemical reactant is allowed tosufficiently exothermically react with the aqueous solution to heat theheating solution to within a first, elevated temperature range. Thesecond chemical reactant is allowed to sufficiently exothermically reactwith the aqueous solution to maintain a second temperature range, whichmay be the same as or different than the first temperature range. Thethird chemical reactant is allowed to sufficiently exothermically reactwith the aqueous solution to maintain a third temperature range, whichmay be the same as or different than either or both of the first andsecond temperature ranges, thereby heating the substance. Typically, thethird chemical reactant is allowed to sufficiently exothermically reactwith the aqueous solution to maintain a temperature range over a longerperiod of time thereby maintaining heat transfer, which may continue toheat the substance or merely inhibit cooling of the heated substance.

In some embodiments, the method further includes adjusting the elevatedtemperature ranges based on the heat capacity of the substance.Appropriate substances (e.g., comestible liquids and solids), elevatedtemperature ranges (e.g., form 200° F. to 250° F.), and various otheraspects of the method are described above (e.g., various self-heatingapparatus embodiments, appropriate chemical solid chemical reactantmixtures, and other aspects of the embodiments described above).

A method of heating a substance in a chamber (e.g., a heating chamber)can include contacting an aqueous solution with a solid chemicalreactant mixture. The aqueous solution is allowed to react with (e.g.,dissolve) the solid chemical reactant mixture thereby producing withintwo minutes a heating mixture having a temperature of at least 200° F.The heating mixture is in fluid contact with the chamber. Finally, theheating mixture is allowed to transfer heat to the chamber whilemaintaining a temperature of at least 200° F. for at least one minutewithin the heating mixture thereby heating the substance. In someembodiments, the temperatures the heating mixture in the reacting stepand the heat transfer step are independently from 200° F. to 250° F.

In another aspect, the present invention provides a method of heating atleast six ounces, preferably between 6-12 ounces, of a liquid to atemperature of at least 120° F. in a chamber (e.g., a heating chamber).The method includes contacting an aqueous solution with a solid chemicalreactant mixture. The solid chemical reactant mixture has a mass of lessthan 100 g. The aqueous solution is allowed to react with (e.g.,dissolve) the solid chemical reactant mixture thereby producing aheating mixture. The heating mixture is allowed to transfer heat to thechamber thereby heating the liquid to at least 120° F. in the chamber.

In some embodiments, the liquid is heated to at least 120° F. withinfive, or more preferable four, three or two minutes of contacting theaqueous solution with the solid chemical reactant mixture. The liquidmay be heated to a temperature of from 130° F. to 150° F. The solidchemical reactant mixture may have a mass of less than 150 g, or lessthan 100 g, or less than 75 g. In some embodiments, the solid chemicalreactant mixture can have a mass of 150 g or more. In some embodiments,the aqueous solution has a volume of less than 100 mL. For example, theaqueous solution can have a volume of 65.0 mL. In some embodiments, theaqueous solution can have a volume of 100 mL or more. The solid chemicalreactant mixture may include magnesium chloride, calcium chloride, andcalcium oxide. The magnesium chloride may be anhydrous magnesiumchloride, dihydrate magnesium chloride, or a mixture thereof.

In some embodiments, the substance is heated using an embodiment of theself-heating container described above. In some embodiments of themethods and apparatuses described herein, the aqueous solution is heatedsufficiently to form steam. The steam condensation on the outer walls ofthe chamber then provides heat to the chamber for heating a substancetherein. In some embodiments, the even distribution of steam (e.g.,within the reaction chamber) provides for substantially uniform heataround the chamber (e.g., heating chamber).

In some embodiments, the self-heating system is configured with thermaltransfer properties configured to control the amount and rate of heattransferred to the comestible substance. In one implementation, theself-heating container is configured to transfer a least 4.2 BTU perounce of comestible substance from the exothermic reaction in thereaction chamber to the comestible substance in the heating chamber. Insome such embodiments, the container is configured to transfer a least4.9 BTU of heat for each ounce of the comestible substance, or a least5.5 BTU of heat for each ounce of the comestible substance from theexothermic reaction to the comestible substance.

In some embodiments of the container, at least 4.2 BTU of heat for eachounce of the comestible substance are transferred from the exothermicreaction to the comestible substance within one minute of the initiationof the exothermic reaction. In some such embodiments, at least 4.9 BTUof heat for each ounce the comestible substance or at least 5.5 BTU ofheat for each ounce of the comestible substance are transferred from theexothermic reaction to the comestible substance within one minute of theinitiation of the exothermic reaction.

Table 1 sets forth minimum amounts of heat generated by exothermicreactions in various embodiments of the container, where the containercontains 6 ounces of water to be heated. Table 1 provides such heatquantities in British Thermal Units (BTU) for a nominal temperaturechange in the mass-averaged temperature the comestible substance and agiven thermal efficiency of the container. Tables 2-4 are similar toTable 1 and set forth minimum amounts of heat generated by exothermicreactions in various embodiments of the container, where the containercontains 8 ounces, 10 ounces, and 12 ounces of water to be heated,respectively,

TABLE 1 Minimum Heat Quantities for 8 oz. of Water (BTU) NominalTemperature Thermal Efficiency Change 60% 70% 80% 90% 60° F. to 145° F.55.4 47.5 41.5 36.9 70° F. to 145° F. 48.9 41.9 36.6 32.6 80° F. to 145°F. 42.3 36.3 31.8 28.2

TABLE 2 Minimum Heat Quantities for 8 oz of Water (BTU) NominalTemperature Thermal Efficiency Change 60% 70% 80% 90% 60° F. to 145° F.73.8 63.3 55.4 49.2 70° F. to 145° F. 65.1 55.8 48.9 43.4 80° F. to 145°F. 56.5 48.4 42.3 37.6

TABLE 3 Minimum Heat Quantities for 10 oz of Water (BTU) NominalTemperature Thermal Efficiency Change 60% 70% 80% 90% 60° F. to 145° F.92.3 79.1 69.2 61.5 70° F. to 145° F. 81.4 69.8 61.1 54.3 80° F. to 145°F. 70.6 60.5 52.9 47.1

TABLE 4 Minimum Heat Quantities for 12 oz of Water (BTU) NominalTemperature Thermal Efficiency Change 60% 70% 80% 90% 60° F. to 145° F.110.8 95 83 73.8 70° F. to 145° F. 97.8 83.8 73.2 65.2 80° F. to 145° F.84.6 72.6 63.6 56.4

In some embodiments, heat is generated by the exothermic reaction in aplurality of stages to expedite heating of the comestible substance. Insome embodiments, a maximum temperature within the reaction chamber 13is attained during a first stage of the multistage exothermic reaction.The maximum temperature within the reaction chamber 13 can be at least212° F. in some embodiments. In some embodiments, the maximumtemperature is reached in 15 seconds or less, 10 seconds or less, fiveseconds or less, two seconds or less, one second or less afterinitiation of the multistage exothermic reaction.

While a high maximum temperature is desirable to expedite heating of thecomestible substance, the structure of the container can becomecompromised, the comestible substance may become too hot to be safelyconsumed, or both if the temperature within the reaction chamber 13becomes too elevated. To inhibit elevation of the temperature within thereaction chamber 13 from becoming too elevated, one or both of the firstcompartment 16 and the second compartment 22 can contain material toabsorb excess heat. For example, a thermoplastic material can becontained in the first compartment 16 along with one or more reactants.The thermoplastic material can be in one or more pieces and can be ingranular form. The thermoplastic material can be configured to beginmelting at or slightly above the desired average temperature of theheating reaction over the intended reaction period. The thermoplasticmaterial preferably has a high enthalpy of fusion. In some embodiments,the material to absorb heat can comprise thermoplastic, wax, polymermaterial, or other materials or combinations thereof. For example,ethylene vinyl acetate (EVA), such as ELVAX™ sold by DuPont, may beused. The EVA preferably has a melting temperature of about 158° F., R&Bsoftening point of about 239° F., and a viscosity of about 1,125 cps@350° F. In one example, about 6 to 10 grams of EVA was added to about62.5 grams of chemical mixture consisting essential of about 10 to 55parts of magnesium chloride, about 10 to 35 parts of calcium chloride,and about 10 to 20 parts of calcium oxide, which lowered the maximumtemperature in the container by at least 10° F.

In some embodiments, the exothermic reaction generates steam during aleast one stage. The reaction can cause steam within the reactionchamber for a period of less than one second, one second, or more thanone second. In some embodiments, steam is generated by the exothermicreaction during the first stage of the multistage exothermic reaction.The steam may rapidly condense upon contact with walls of the container,for example, the inner container body 14. Condensation of steam on thewalls of the container that separate the reaction chamber 13 from theheating chamber 15 can advantageously rapidly transfer heat to thosewalls of the container, thereby expediting transfer of heat to thecomestible substance in the heating chamber 15. Steam, however, can alsocause the internal pressure of the container to increase, therebyincreasing the risk of the container rupturing. As such, the containersof certain preferred embodiments of the present invention are designedto withstand a higher rupture pressure. In one implementation, thecontainer has an inner and outer container body that are connected by adouble seam as described above. In another implementation, the containerincorporates a seal plate, which serves not only as a barrier member asdescribed above, but also structural reinforcement for the container.The seal plate preferably comprises a rigid, circular ring-likestructure that extends annularly along the interior wall of thecontainer. The seal plate and double seam features both providestructural reinforcement to the container so that the container iscapable of withstanding higher internal pressures. In one embodiment,the container is capable of withstanding an internal pressure of betweenabout 40-45 psi, more preferably at least 42 psi, as measured inaccordance with ASTM F1140-07.

In some embodiments, the exothermic reaction produces a heating mixturewithin the reaction chamber 13 that has an average temperature of aleast 167° F. over one minute from the initiation of the exothermicreaction. In some embodiments, the exothermic reaction produces aheating mixture within the reaction chamber 13 that has an averagetemperature of a least 170° F. over one minute. Table 5 sets forthminimum average temperatures of the heating mixture over a period of oneminute to effect the stated nominal temperature changes within oneminute for the stated coefficients of heat transfer between theexothermic reaction and the comestible substance, where the ratio of thesurface area of the inner container body 14 that is contacted by theheating fluid as measured in square inches is three times greater thanthe volume of the comestible substance as measured in cubic inches.

TABLE 5 Minimum Average Temperature (° F.) of the Heating Mixture 3:1S/V Nominal Heat Transfer Coefficient Temperature (ft² · sec. · ° F.)Change 0.0167 0.0278 0.0556 0.0833 60° F. to 145° F. 293 234 190 175 70°F. to 145° F. 276 224 184 171 80° F. to 145° F. 258 213 179 167

The heat transfer coefficient of 0.0167 BTU/(ft²·sec.·° F.) may requirelittle or no agitation of the reaction mixture, while the heat transfercoefficient of 0.0833 BTU (ft²·sec.·° F.) may require a vigorousagitation of the reactant mixture.

A reactant mixture with high boiling point would tend to improve heattransfer. An aqueous system can employ a controlled salt to water ratioto increase the boiling point of the reactant mixture. For example, insome embodiments, the solid reactant mixture can comprise a relativelylarge fraction of reactants that dissolve in water, such as magnesiumchloride and calcium chloride, compared to reactants that do not, suchas calcium oxide.

In some embodiments, the heating chamber 15 can be opened after a periodof time has elapsed since the initiation of the exothermic reaction. Forexample, in some embodiments, the heating chamber 15 is openedapproximately two minutes after initiation of the exothermic reaction.In some embodiments, the heating chamber can be opened less than twominutes after initiation of the exothermic reaction. For example, insome embodiments, the heating chamber 15 can be opened approximately 60seconds or less after initiation of the exothermic reaction.

The comestible substance is preferably sufficiently warm to be consumedwhen the heating chamber 15 is opened. In some embodiments, when theheating chamber 15 is opened, the temperature of the heating mixture inthe reaction chamber 13 is at least as great as the temperature of thecomestible substance. In some embodiments, the temperature of thereactant mixture exceeds the temperature of the comestible substancewhen the heating chamber 15 is opened by no more than 30° F., no morethan 25° F., or no more than 20° F. In some embodiments, it may bedesirable that the temperature of the reactant mixture exceed that ofthe comestible substance when the heating chamber 15 is opened tothereby maintain the temperature of the comestible substance over aperiod of time after the heating chamber is opened. In some embodiments,the exothermic reaction may continue to produce heat for one minute, twominutes, five minutes, 10 minutes or more after the heating chamber 15is opened to inhibit cooling of the comestible substance. However, insome embodiments, the exothermic reaction can be configured such thatthe temperature of the reactant mixture, the rate of heat generation bythe exothermic reaction, and rate of heat transfer to the comestiblesubstance are not sufficiently large to cause the temperature of thecomestible substance to increase significantly after the heating chamber15 is opened.

In some embodiments, wherein the solid chemical reactant mixturecomprises at least two solid reactants in granular, particular, orpowder form that are contained in the same compartment prior toactivation of the exothermic reaction, transportation of the containermay cause the reactants to settle and stratify within the chamber. Insome embodiments, such stratification may adversely affect theexothermic reaction. To avoid stratification of the reactants duringtransportation, at least a first solid reactant and a second solidreactant can have average grain sizes that are approximately equal. Insome embodiments, at least the first solid reactant and the second solidreactant have average grain sizes that differ by no more than 10%.

IV. EXAMPLES

The following examples are meant to illustrate certain embodiments, andare not intended to limit the scope of the invention.

Examples 1-4

700 grams of calcium chloride dihydrate, 200 grams of magnesium chlorideanhydrous and 200 grams of calcium oxide is mixed together in a beakerwith a spatula until the powders are thoroughly mixed. In a separatecontainer a 5% solution of lactic acid in distilled water is mixed.Sixty-three grams of the 5% lactic acid was placed in a bottom enclosedcompartment of a heat cup and 35 grams of the powder mix was loaded intoan upper enclosed compartment. The drinking cup, which serves as aheating chamber, was filled with water. The cup was activated by pushinga button on the bottom thereby breaking the breakable partition betweenthe bottom and upper enclosed compartments, then shaking for 30 seconds,and then letting sit. After a total of two minutes the drinking liquidwas 105° F. The exact same experiment was repeated with the exception ofusing 45 grams of the powder and the drinking liquid in the heatingcompartment reached 116.2° F. Again, the experiment was repeated with 55grams of powder and the temperature reached 0.131.8° F., and when 65grams of powder was used the drinking liquid reached 149.3° F.

Example 5-7

In a small beaker 35 grams of calcium chloride was mixed with 10 gramsof magnesium chloride and 10 grams of calcium oxide in a first enclosedcompartment. The liquid cup contained 65 grams of 10% lactic acidsolution in a second enclosed compartment when the cup was activated bybreaking a breakable partition, whereupon the temperature reached 144.5°F. Two more drinking cups with the exact same contents were constructedand one cup reached 141.2 F and the other was 146.3° F. The heatingchambers of the drinking cups in these three examples were filled withwater as the medium to be heated.

Examples 8-10

In the next set of examples the bottom enclosed compartments contained asolution that was 15% lactic acid and 0.5% sodium lauryl sulfate indistilled water. The bottom enclosed compartments were filled with 65grams of this solution. In the first example the heating chamber of thedrinking cup was filled with tea, and an upper enclosed compartmentcontained a dry powder composed of 35 grams of calcium chloride, 10grams of calcium oxide and 10 grams of magnesium chloride. Whenactivated by breaking a breakable partition between the upper and bottomenclosed compartments, the temperature was 137.8° F. Another cup wasmade the exact same way but contained water in the beating chamber ofthe drinking cup and the temperature reached 143.4° F. A third cup wasprepared with the same lactic acid-sodium lauryl sulfate solution in thebottom enclosed compartment, and the powder contained 38.5 grams ofcalcium chloride, 11 grams of magnesium chloride and 11 grams of calciumoxide. The heating chamber of the drinking cup contained apple cider andthe temperature of the cider when activated was 147.4° F.

Example 11

Ten cups were prepared exactly the same way as in above Examples 8-10.The bottom enclosed compartment contained 65 grams of a 15% solution oflactic acid and a 0.5% solution of sodium lauryl sulfate. The powder inthe upper enclosed compartment was 35 grams of calcium chloride, 10grams of magnesium chloride, 10 grams calcium oxide. Five of thedrinking cups were filled with apple juice in the heating chamber andthe temperature upon activation ranged from 124.4° F. to 150.2° F. Theother five cups were filled with tea in the heating chamber and uponactivation by breaking a breakable partition between the upper andbottom enclosed compartments. The temperature ranged from 125.0° F. to153.1° F.

Examples 12-13

Two cups were prepared as in example 11. The heating chamber drinkingcup contained tea. After the samples were prepared they were placed inthe freezer for 24 hours before activation. They were removed from thefreezer and activated immediately by breaking the breakable partition.The tea of one reached 125.0° F. and the other reached 122.1° F.

Examples 14-15

Two cups were prepared as in example 11 and also contained tea in theheating chamber of the drinking cup. After the samples were preparedthey were placed in the refrigerator for 24 hours before they wereactivated. Upon activation by breaking the breakable partition, the teain one reach was 138.2° F. and the other was 142.7° F.

Examples 16-17

Again two cups were prepared as in example 11 and also contained tea inthe heating chamber of the drinking cup. After the samples were preparedthey were placed on a shaking table for 24 hours to simulate shippingconditions. Upon activation by breaking the breakable partition, the teain one cup reached 153° F. and the other was 160° F.

Examples 18-21

In these four examples the powder was 35 grams of calcium chloride, 10grams of magnesium chloride, and 10 grams of calcium oxide. The heatingchamber of the drinking cup contained tea in all four examples. In thebottom enclosed compartment the lactic acid was replaced with 15% aceticacid in one case, 15% oxalic acid in one case, 15% gluconic acid inanother case and 15% propionic acid in the last case. They all contained0.5% sodium lauryl sulfate. Upon activation by breaking the breakablepartition, the tea in the acetic acid cup reached 122.0° F., the oxaliccup 132.6° F., the gluconic acid cup 126.0° F. and the propionic cupreached 130.5° F.

Examples 22-25

In these two examples technical grade calcium oxide instead of reagentgrade calcium oxide was used. The heating chamber of the drinking cupcontained tea and the temperatures of the tea in the heating chamberreached in 143.6° F. and 143.4. From this experiment it was determinedthat the calcium oxide could be purchased using a lower grade ratherthan reagent grade calcium oxide. In another test the heatingcompartment was filled with juice instead of tea and the temperaturereached 141.4° F. and 139.0° F.

Examples 26-31

In the following examples the dry powders were not mixed. They werelayered in the enclosed chambers to determine whether mixing thechemicals affects performance. The dry powders in this experiment were38.5 grams of calcium chloride, 11 grams of magnesium chloride and 11grams of calcium oxide. The bottom enclosed compartment contained the15% lactic acid and 0.5% sodium lauryl sulfate solution and the heatingchamber of the drinking cup contained water. See Table 1 for theresults.

TABLE 6 Cup Number First Layer Second Layer Third Layer H₂O Temp. 1Calcium Oxide Calcium Magnesium 141.5 F. Chloride Chloride 2 CalciumMagnesium Calcium Oxide 148.0 F. Chloride Chloride 3 Magnesium CalciumOxide Calcium 129.0 F. Chloride Chloride 4 Magnesium Calcium CalciumOxide 131.5 F. Chloride Chloride 5 Calcium Calcium Oxide Magnesium 143.0F. Chloride Chloride 6 Calcium Oxide Magnesium Calcium 133.5 F. ChlorideChloride

Example 31-34

In these examples the dry chemicals were ground in a mill. The dry mixcontained 38.5 grams of calcium chloride, 11 grams of magnesiumchloride, and 11 grams of calcium oxide. In the first cup the heatingchamber of the drinking cup contained water and upon activation bybreaking a breakable partition the temperature of the water was 145.0°F. In the second cup the heating chamber of the drinking cup containedjuice and the temperature was 139.6° F. The other two cups contained teaand one reached a 143.2° F. and the other was 136.6° F.

In the next eleven examples the dry chemicals were all ground in agrinder and dried in the oven. The mix contained 38.5 grams of calciumchloride, 13.0 grams of magnesium chloride and 11.0 grams calcium oxide.The bottom enclosed containers contained the 15% lactic acid with 0.5%sodium lauryl sulfate solution. Six cups contained tea and uponactivation by breaking a breakable partition the temperature of thewater in the heating chamber ranged from 126.7° F. to 139.1° F. In theother five cups the temperatures ranged from 136.8° F. to 143.6° F.

Example 46-47

In these examples the bottom enclosed container contained 20% lacticacid and 0.5% sodium lauryl sulfate solution and the heating chamber ofthe drinking cup contained water but the dry chemicals only contained 30grams of calcium chloride and 28 grams of calcium oxide. The temperatureupon activation was 141.0° F. A second cup contained 25 grams of calciumchloride and 25 grams of calcium oxide and the water temperature uponactivation was 135° F.

Examples 48-49

In these examples the bottom enclosed container contained 20% tacticacid and 0.5% sodium lauryl sulfate solution and the heating chamber ofthe drinking cup contained water and the dry chemicals mix contained 35grams of calcium chloride and 18 grams of calcium oxide and 2 grams ofmagnesium chloride. The temperature of the water upon activation was140.5° F. and 138.0° F.

Example 50-59

In these nine examples the bottom enclosed container contained the 15%lactic acid solution with the 0.5% sodium lauryl sulfate and the drypowder was ground and placed in the oven. The dry mix contained 35 gramsof calcium chloride, 15 grams of magnesium chloride and 15 grams ofcalcium oxide. All the heating chambers of the drinking cups containedwater and the temperature ranged between 130.6° F. and 144.0° F. in allnine cups upon activation.

Example 60

Ten self-heating containers constructed with the double seam and sealplate as described above were tested for internal pressure failure pointin accordance with ASTM Method F1140-07 “Standard Test Methods forInternal Pressurization Failure Resistance of Unrestrained Packages”.See Table 7 for results.

Micrometer Cup Number Measurements Psi at Rupture 1 0.098, 0.099, 0.09845 2 0.098, 0.100, 0.100 45 3 0.098, 0.098, 0.099 45 4 0.098, 0.097,0.099 45 5 0.101, 0.102, 0.100 45 6 0.104, 0.104, 0.105 46 7 0.097,0.098, 0.099 42 8 0.098, 0.097, 0.100 43 9 0.098, 0.097, 0.098 43 100.100, 0.101, 0.102 40

Although the inventions have been disclosed in the context of certainpreferred embodiments and examples, it will be understood by thoseskilled in the art that the present inventions extend beyond thespecifically disclosed embodiments to other alternative embodimentsand/or uses of the inventions and obvious modifications and equivalentsthereof. In addition, while several variations of the inventions havebeen shown and described in detail, other modifications, which arewithin the scope of the inventions, will be readily apparent to those ofskill in the art based upon this disclosure. It is also contemplatedthat various combinations or sub-combinations of the specific featuresand aspects of the embodiments may be made and still fall within thescope of the inventions. It should be understood that various featuresand aspects of the disclosed embodiments can be combined with orsubstituted for one another in order to form varying modes of thedisclosed inventions. Thus, it is intended that the scope of at leastsome of the embodiments of the present inventions herein describedshould not be limited by the particular disclosed embodiments describedherein.

What is claimed is:
 1. A container for a comestible substance,comprising: an outer body, said outer body having a height of betweenabout 5 to 8 inches and an average cross-sectional area of between about3 to 4 square inches; a heating chamber disposed within the outer body,said heating chamber having a volume adapted to receive between about 10to 18 fluid ounces of a comestible substance; a reaction chamberdisposed within the outer body, said reaction chamber is adapted tohouse a predetermined amount of reactants and allow the reactants toundergo an exothermic chemical reaction and generate heat; and whereinthe coefficient of heat transfer from the reaction chamber to thecomestible substance is at least between about 0.0167 BTU/(ft²·sec.·°F.) to 0.0833 BTU/(ft²·sec.·° F.) such that the temperature of thecomestible substance can be raised from room temperature to about 145°F. within one minute of the initiation of the exothermic chemicalreaction and that the temperature of the comestible substance doesexceed about 212° F.
 2. The self-heating container of claim 1, wherein atemperature within the reaction chamber is at least at great as thetemperature of the comestible substance after two minutes have elapsedsince initiation of the reaction of at least a first reactant and asecond reactant.
 3. The self-heating container of claim 1, wherein eachof the second reactant and the third reactant are in granular form, thedifference between an average grain size of the second reactant and anaverage grain size of the third reactant being equal to or less then 10percent.
 4. The self-heating container of claim 1, further comprising alayer of insulation disposed within the reaction chamber.
 5. Theself-heating container of claim 1, wherein the first reactant compriseswater, the second reactant comprises magnesium chloride, and the thirdreactant comprises one of calcium chloride and calcium oxide.
 6. Theself-heating container of claim 5, further comprising at least a fourthreactant located within the reaction chamber, said fourth reactantcomprises a thermoplastic material.